RAMSEY, Minnesota (CNN) -- Toxicology tests for Prince concluded that the entertainer died from an accidental overdose of the opioid fentanyl, according to a report on his death by the Midwest Medical Examiner's Office.

Fentanyl, prescribed by doctors for cancer treatment, can be made illicitly and is blamed for a spike in overdose deaths in the United States. It's 25 to 50 times more potent than heroin and 50 to 100 times more potent than morphine, according to the U.S. Drug Enforcement Administration.

Prince, whose full name was Prince Rogers Nelson, died April 21 at age 57, after being found unresponsive in an elevator at Paisley Park, his home and recording studio in Chanhassen, Minnesota.

The report from the medical examiner's office, which was released on Twitter, didn't provide many details. "How injury occurred: The decedent self-administered fentanyl," the report said. For manner of death, a box was marked for "accident."

The report didn't specify how the drug was taken and if the fentanyl was prescribed or illegally made.

The music superstar weighed 112 pounds and was 63 inches tall when he died, the report said. He was wearing a black cap, shirt, pants, boxer briefs and socks and a gray undershirt, the report said. His occupation was listed as "artist" and his business as "music."

The full autopsy and toxicology reports will not be released, the office told CNN.

Since his death, information has emerged about the entertainer's alleged abuse of prescription drugs.

A law enforcement source told CNN's Evan Perez in April that the entertainer was found with opioid medication at the time of his death. Investigators so far haven't found any indication that Prince had a valid prescription for the recovered opioid medications

An attorney for Prince's half-siblings said they revealed the singer had an addiction to Percocet decades before he died. One half-sibling said Prince started using the drug to help him deal with the rigors of performing, not for recreational use.

On April 15, on his way home after performing in Atlanta, Prince's plane made an emergency landing in Moline, Illinois. Prince was unresponsive and taken to a hospital. A law enforcement official told CNN he was treated for a potential overdose of pain medication.

The day before Prince died, his team called an eminent opioid addiction specialist in California seeking urgent help for the singer, an attorney working for the specialist and his son said.

The specialist, Dr. Howard Kornfeld, couldn't get there immediately so he sent his son, Andrew Kornfeld, on an overnight flight to Minnesota. The goal was for the younger Kornfeld to help evaluate Prince's health and encourage him to enter treatment for pain management and potential addiction issues, attorney William Mauzy told reporters.

But by the time Andrew Kornfeld arrived at the singer's Paisley Park complex on the morning of April 21, it was too late. He and two Prince representatives found the 57-year-old entertainer unresponsive in an elevator. Andrew Kornfeld was the person who called 911, Mauzy said.

Authorities have also said the investigation into Prince's death is a criminal investigation. It was not immediately clear if Kornfeld is the subject of a separate investigation.

Federal prosecutors and the Drug Enforcement Administration are investigating how Prince obtained prescription medications and from whom, the agencies said.